Process of making nitrates



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Patented July 3, 1923.

HEINRICH HAMPEL, OF'HALLE, GERMANY.

PROCESS 0F MAKING NITRATES.

Application led April 7, 1921. Serial No. 459,203.

To all whom it may concern:

Be it known that I, HEINRICH HAMPEL, a subject of the German State, andresident of Halle, in the State of Prussia, Germany, have inventedcertain new and useful Improvements in a Processof Making Ni.

trates (for which I have filed applications in Germany, Mar. and 31,1919); and do hereby declare the following to be a full, clear, andexact description of the invention, such as will enable others skilledin the art to which it pertains to make and use the same. y

The present invention consists in a cyclic proce b v the use of which itis possible to react with a suitable substance on salts of a strongacid, and obtain a corresponding salt of a weaker acid in those cases,where the weaker acid cannot precipitate the salt directly or at leastonly incompletely and to reproduce the reacting substance for returninto the cycle of operations forusemwithma new quantity of strong acidsalt. This process is of particular importance for producing of nitratesof potassium, sodium or magnesium.

l shall give at first a general description of this process, which willbe explained by some examples below.

By the letters A and B may be indicated two dierent metal radicals ororganic radicals. By y and z be indicated three radicals of an acidexplained below. The kind and application of the acids will be f evidentin course of the further presentaor at least only incompletely. Forobtain ing the transformation another metal B is taken, forming thethree combinations Bw, By/ and Bz, in which and y are the radil cals ofthe acids above mentioned and z is a radicah the qualities of which willbe hereinafter given.

0f the three combinations of the metal B the By salt may be easilysoluble, then Bm and Bz must be difiicultlyv soluble at least incomparison to By. Besides Ba must be more soluble than Bz.

The followingl conditions are necessary for the acid radical a: If it isthe radical of an oxy n acid (say for example HZCO3 or ILSO3 theanhydrid of acid Z, (perhaps CO2 or SO2) must be capable of effectingthe following reaction with a suitable base:

2NH3+Z+H2O= (NH4) QZO: (NH4) 2a.

for example However if the acid Hz does not 'contain 65 oxygen (H2S orHC1), the following reaction must be possible:

which latter condition howeyer comes less finto consideration.

After having discovered the combinations Bm, Bg/ and Bz conforming tothesalt of metal Am and to the transporting acid Hy in regard to theconditions mentioned above l can explain the process following by'general formulae, which will later.

The salt Am is dissolved and then the salt of the transforming acid (By)is added when the following reaction results:

The sait Ba being difficuluy Soluble is precipitated. The required saltAy can be removed frorn the solution which has been sepp be changedarated from the precipitate by boiling perhaps.

The precipitated salt Bw which should be difiicultly soluble relativelyto Ay, now is dissolved suitably in a greater quantity of liquid andserves for the reaction b."

1. if Hz is an Oxy-acid havin an' anhydrid Z, the reaction is thefollowing:

In both cases the salt Bz is precipitated, because it is morediflicultly solu le than Bw.

Bz+Hg/:By-1Hz. In this manner I have a cyclic process.

, In the place of NH3 or (NHQOH -also l l other hydroxides may beemployed, for example NaOH or KOH.

` Eampzes.

l. The manufacturing of potassium (ori sodium-or magnesium) nitratesfrom their sulphates.

a. Kzsorpcauroa)Panno,Maso,`

To the concentrated Solution of potassiuuil sulphate, calcium nitrate isadded, ltill all the'sulfuric' acid is precipitated as CaSO. Afterhaving precipitated and separa-ted from the solution the sulfate ofcalcium thus formed, the precipitate is transformed to carbonate ofcalcium by means of ammonia and carbondioxide.A

b. casoennaJrcoz-pnzo:

CaCU3+ (NHQzSO,v Finally the precipitated carbonate of calcium istreated by nitric acidforming the nitrate of calcium and carbondioxlde,which escapes as a gas:

c. sacos-pennes:

Gamm-Cosmo Other examples.

Ilf'lhe manufacturing of iodide of aluminium from sulfate of aluminium:

a. ,A1,(so.),Jracai2mm-acaso4 a. scasoennsnzomcd:

- ecacoamnazso,

HI. The manufacturing of acetate of sodium from chloride of sodium:

A. With carbon dioxide:

Laedeae a. ras-pani(czrisop=ri2s+ri (cano.)2

IV. The manufacturing of `chloride of magnesium from sulfate ofmagnesium:

, A. With ammonia used in the cycle: af. MgS04+CaCl2=CaSOri-MgCl. b.CaS04-l-2NH8-l-C02+H2O:

CaCVl-(NHQQSO4 c. CaCOa-l-QHCl:CaClE-I-COH-ILO B. In connection withanother base, for example hydroxide of potassium used in the cycle:

Otherh droxides than hydroxide of ammonium s ould be employed chiefly inthe producing organic compounds..

V. Themanufacturin of nitrate of alkali (as potassium, from theirchlorides.

As the above example for producing the acetate of sodium (HI)demonstrates, the process is not limited to the production of salts ofinorganic acids, it is also suitable to the production of salts oforganicacid's.

Alsoit is possible by employing the process so ium, magnesium) above, toet salts with organic radicals, if

In the processes given above and their uses, the individual reactions orpartial reactions may be known, but what is new and wherein lies thisproces, is the novel comle to get with these reactions of binations ofthese partial reactions and the use of the differences in'solubilitywhereby a continuous process operating in a cycle is obtained. Thiscycle of reactions is of great importance forthe technical execution ofthe process. The discovery of the general rule formin a proce in aclosed cycle is the essentie oint` of the invention.

The cyclic c ara/ eter of the process enables an advantageousarrangement of apparatus, very profitable for technical use.

It reduces all the losses in the manufacturing, avoids ltration andwashingsof precipitates--an evil very expensive and troublesome in thechemical industry and avoids any transport of the intlmedilycombinations.

. sodium chloride, the NaCl contained inthe raw salt remainssubstantially indissolved. 0n the cooling down 'of the lye, combinationsO calcium and magnesium are chiefly precipitated. The final productsreceived from the raw salts containing chie-fiy NaCl with an end productsubstantially of KCl, MgN()3 and these are employed as a fertilizer andconsist of potassium-magnesia-saltpetre- In the same manner, theproportion of compounds of magnesium rises in the final product, when Mg(NO3)2 is made from kieserite containing NaCl.

Producing nitrate of potassium from the corresponding raw salts, thereaction may also be effected by nitrate of. magnesium, that preferablyis to be used in concentrated solution to eect the reaction:

mowing-(Nos),=2KNo,+Mgc1,.

i The most essential part of the apparatus used for the new proce isrepresented byl the subjoined drawing. In the description it issupposed, that nitrate of potassium and sulphate of ammonium are to beobtained. It is evident, that it can be used also for .other processeswith similar reactions, espe'- cially in the production of nitrate ofpotassium and chloride of ammonium from their eaV chlorides (ExasmpleV).

There are two 'reaction vessels 1 and 2 working alternately, furnishedwith an ap'- paratus for stirring. At first the precipltation of thecarbonate' and then the solution of the carbonate takes. place. AIn thedrawing the carbonate of calcium in 1 is precipitated. Through theconduit 4.- the necessary solution of sulphate of calcium is supplied.Through the main conduit 14 and pipe 6 ammonia `is blown. Thecarbondioxide necessary for the reaction is supplied by p ipe 7. Bythesemeans carbonate of calcium is precipitated. After the precipitation thesolution in the vessel is removed through pipe 5 and employed for thesolution of another quantity of sulphate of calcium formed by thereaction. Then the reaction begins again. This is continued tillsufficient sulphate of ammonium is formed in the solution whereupon thelatter can be obtained in the known manner by evaporation.

At the-same time and in connection with the .vessel 1, the vessel 2 'ofthe same form'.

is workin During the precipitation of carbonate 1n the rst vessel, thesolution of the carbonate and the formation of the carbondioxide,necessary for the first vessel, here takes place.

In the vessel 2 there is a precipitate of carbonate of calcium,resulting from the reaction which was ended in it (process b).Through'vpipe the nitric acid is supplied, whilst the neutralizedsolution returns through pipe 9 t0 the towers serving for the absorptlonof nitrous gases, in order to supply new quantities of nitric acid. Thatis continued till sufiicient nitrate of calcium is obtained and which isto be reactions (a).

The carbondioxide escaping from the solution of the carbonate isconducted throu h the plpes 10 and 15 to 7, serving for t eprecipitation in the first vessel.

The drawing shows the manner and the form of the vessels for reactionand their connection with the principal pipes, so arranged that thevessels can be employed either for precipitation or solution ofcarbonate of calcium by a simple manipulation' of the valves.

The sulphate 4of calcium is conducted to and from the vessel throughipes 16 and employed inthe A'IIS 17, while through 18 and 19 t e weakacid Y is conducted to andfrom said veel. The.

pipes and connections out of use are represented by dotted lines in thedrawing or signified by dotted arrows. They are workmg when the vesselsare reversed, i, e.. if the solution is made in 2, and the precipitationin 1. In this case through pipe 11 ammonla and pipe 12 carbondioxide 1sintroduced during the time that carbondioxide originated by the'actionlof the nitric acid is escaplng.

The arrangement of the apparatus gives remarkable advantages. At firstthe carbonate of calcium remains as an intermediate material in thevessels, a very profitable thing considering. that the carbonate ofcalclum often is precipitated on the walls of the vessels and that inother processes it is necessary to take particular precautions to pre'vent it (as in the process of manufacturing sul hate of ammonium fromgypsum).

n the arrangement above this evil is turned to an advantage, for thecarbonate of calcium covering the walls of the vessels protects themfrom the attacks of the nitric acid necessary for the sOutions.

The solution or the precipitation of sulphate of calcium may at the sametime be efected with the precipitation or the solution of carbonate inthe same vessel. In this manner also the transport of this material .isavoided and separate vessels for the precipitation or the solution arenot necessary.

' The described apparatus gives also other advantages by avoiding theloss of carbondioxide necessary for the precipitation and` if theproducing of especially pure products is done-each filtration andwashing of precipitates is avoided, because it is impossible, that thereis a loss by an unexact separation 'of the solutions from theprecipitations. i

Finally, the diagrammatic representation of the apparatus, while showingbut two vessels, may be considered as two rows .of such vesselsoperating alternatively. Such rows may then operate by the principle ofcounter-current, acknowledged in the industry, and be joined in twocolumns connected to each other.

l claim:

1. A cyclic process which comprises reacting on a solublesalt of astrong acid with a reagent comprising a. soluble salt of a weaker acidhaving a different base, andv forming a diiicultly soluble salt of thestronger acid containing the base of the vweaker acid salt and a solublesalt of the weaker acid with the base of the stronger acid salt, andconverting the diiicultly soluble salt of the stronger acid combinedwith the base of the weaker acid salt into the original reagent forreaction on a fresh quanti-ty of strong acid salt.

'2. A cyclic process, which comprises reacting on a soluble salt of astrong acid with a reagent comprisinga soluble salt of a weaker acidhaving a different base and forming a ditiicultly soluble l salt of thestronger acid and the base of the weaker acid salt, and a soluble saltof the weaker acid with the base of the stronger acid salt, separatingthe two salts, convertingr the former by a soluble base and an acid intoan intermediate product and converting the intermediate product into theoriginal reagent for action on fresh quantities of strong acid salt,

3. A cyclic process, which comprises reacting on the soluble salt of astrong acid with a reagent comprising a salt of a weaker acid having adi'lerent base, thereby forming a diiicultly soluble salt and a desiredproduct, treating the diliicultly soluble salt with a base and a gaseousacid to form an easily soluble salt and an insoluble salt., and treatingsaid insoluble salt with acid of the reagent in free form to reform saidreagent or return into the cycle of operations.

4. A process, which comprises reacting on the soluble salt of a strongacid with a reagent comprising a salt of a weaker acid4 having adifferent base, thereby forming a difiicultly soluble salt ot thestronger acid and a desired product, treating the difiiculty solublesalt with a base and carbon dioxide thereby forming an easily solublesalt and an insoluble salt, and treating said insoluble accuses and adesired product, treating the difiicultly soluble salt with an alkalinebase and carbon dioxide thereby forming an easily soluble salt and aninsoluble salt, and treating said insoluble salt with a free acidcapable of reforming said reagent.

6. A process, which comprises reacting on the soluble salt of a strongacid with a reagent comprising a salt of ,a weaker acid having adifferent base, thereby forming a difiicultly' soluble salt of thestronger acid and a desired product, treating the difficultly solublesalt wit-h ammonia and carbon di'- oxide thereby forming an easilysoluble salt and an insoluble salt, and treating said insoluble saltwith a free acid capable of reforming said reagent.

7. A process which comprises reacting on a soluble sulphatewith asoluble nitrate of a diilerent base, thereby forming a diiiicult- 1ysoluble sulphate and a soluble nitrate, converting the latter sulphateinto a more insoluble salt and converting the latter salt into nitratefor vreturn into the cycle of operations.

8. The process which comprises reacting on a soluble alkali metalsulphate with calcium nitrate, thereby forming calcium sulphate andalkali metal nitrate, converting the calciumsulphate into a moreinsoluble salt and reacting on the latter to re-form calcium nitrate. c

9. The process` which comprises reacting on potassium sulphate withcalcium nitrate, thereby forming calcium sulphate and potassium nitrate,reacting on the latter sulphate process which comprises reacting on vwith a base and a weak acid anhydrid to` form a more insoluble calciumsalt of said acid and converting the latter salt into calcium nitrate.

10. The process. which comprises reacting on potassium sulphate withcalcium nitrate thereby forming calcium sulphate and potassium nitrate,reacting` on the latter sulphate with a soluble base in the presence ofcarbon dioxide. thereby forming a soluble sulphate oi? said base andcalcium carbonate, reacting on the carbonate with nitric acid to re-formcalcium nitrate and carbon dioxide` and returning both into the cycle ofoperations.

li. The process, which comprises reacting on a soluble salt of a strongacid with a reagent comprising a soluble salt of a weaker acid havinganother base` thereby forming a soluble desired product and adifiicultly soluble salt, reacting on the latter salt with a base and aweak acid gas, thereby torming an easily soluble salt and a salt of saidas my invention, I have signed by name in acid gas, reacting on saidacid gas salt with presence of two subscribing witnesses. acid tore-form said reagent and liberate the ET 'i Weak acid ,gas and returningboth reagent HEIRHH HAMPEL DR PHIL 5 and liberated gas into the cycle ofopera- Witnesses:

tions. REINHARD VoGT,

In testimony that I claim the foregoing HERMANN ALTHAUR.

